This present invention relates generally to manufacturing objects. More particularly, the invention provides a method and apparatus for fabricating and operating electro-mechanical systems. Merely by way of example, the invention has been applied to a high fill factor micro-electro-mechanical mirror array with a hidden, flexible support pedestal. The method and apparatus can be applied to other electro-mechanical technology as well, including actuators and sensors.
Micro-electromechanical systems (MEMS) are used in a number of application areas. For example, MEMS have been used in micro-mirror arrays, sensors, and actuators. In some of these applications, a suspended member is supported by a flexible hinge attached to a stationary portion of the mirco-mirror array. Flexibly attached to the hinge, the suspended member is attracted to an electrode upon application of an electrical force and restored to an original position by a restoring force. In this manner, the array of micro-mirrors can be tilted in relation to a light source. In some applications, it is beneficial to have the hinge located beneath the micro-mirror surface in a hidden position, enabling the fill factor of the array to be increased. As the fill factor of the micro-mirror array is increased, the potential quality of two-dimensional images created by optical systems using the array is improved.
As merely an example, conventional MEMS have utilized various micro-mirror designs to hide the hinge in a location behind the mirror surface. For example, torsion spring hinges attached to the backside of the mirror surface have been used in some designs. Unfortunately, these techniques also have limitations. For example, some torsion spring designs are difficult to manufacture owing to their complex structural features. Moreover, complex mechanical structures may have reliability and lifetime concerns. Therefore, there is a need in the art for methods and apparatus for a high fill factor micro-electromechanical mirror array with a flexible, hidden support member.